Abstract: An elevator tension member is presented that has one or more steel cords as strength members that are encased in a jacket of thermoplastic polyurethane elastomer. The thermoplastic polyurethane elastomer is selected on the basis of its thermal properties in that the glass transition temperature of the hard phase (Tg HS) is above 90° C. In preferential embodiments that thermoplastic polyurethane elastomer has a crystallisation temperature (Tg) that is at least 20° C. higher than Tg HS. In other preferential embodiments the sum of Tg HS and Tc is higher than 200° C. Such thermoplastic polyurethane elastomers exhibit an unexpected increase in useful lifetime when compared to conventionally used polyurethanes. Moreover the invention provides a simple method to select an appropriate thermoplastic polyurethane elastomer.

Abstract: An elevator tension member is presented that has one or more steel cords as strength members that are encased in a jacket of thermoplastic polyurethane elastomer. The thermoplastic polyurethane elastomer is selected on the basis of its thermal properties in that the glass transition temperature of the hard phase (Tg HS) is above 90° C. In preferential embodiments that thermoplastic polyurethane elastomer has a crystallisation temperature (Tg) that is at least 20° C. higher than Tg HS. In other preferential embodiments the sum of Tg HS and Tc is higher than 200° C. Such thermoplastic polyurethane elastomers exhibit an unexpected increase in useful lifetime when compared to conventionally used polyurethanes. Moreover the invention provides a simple method to select an appropriate thermoplastic polyurethane elastomer.